Nutrients provided by foods mainly do two functions viz. provide energy and maintain structure & function of body. Alcoholics often eat poorly and eat unbalanced diet. This limits the supply of essential nutrients affecting both energy supply and structure maintenance. Furthermore alcohol also affects digestion, storage, utilization of nutrients. Major effects on nutrition due to chronic alcohol consumption are as listed below:

Nutrient deficiencies

Chronic alcoholics may consume more than 50% of the energy from alcohol negating important food groups. Even food intake is sufficient; it impairs the mechanism of blood glucose control leading to either hyperglycemia or hypoglycemia.

Alcohol impairs digestion by inhibiting secretion of digestive enzymes from pancreas. It also impairs absorption of nutrients by damaging the cell lining of stomach and intestine

Nutrient deficiency due to alcohol consumption also impairs absorption of other nutrients. For example: Folate deficiency in intestinal cells causes improper absorption of water, sodium, glucose and additional folate.

Alcohol also impairs storage of vitamin A in liver while causes increased excretion of fats without proper utilizing them.

Researches suggest alcohol causes the impaired digestion and production of protein this leads to difficulty in maintaining structure of cells.

Chronic heavy drinking leads to deficiency of many vitamins and minerals primarily due to inadequate intake and may be also due to disrupted absorption, metabolism and utilization.

Deficiencies of minerals like calcium, magnesium, iron and zinc are common in alcoholics. Decreased calcium absorption is due to fat and vitamin D malabsorption, magnesium deficiency is due to insufficient intake, vomiting, dirrhoea & urinary excretion; iron deficiency is due to gastrointestinal bleeding, zinc deficiency is related to other nutrient deficiency.

Mineral and vitamins deficiency can lead to various medical complications like skin lesions, bone diseases and others.

Medical complications

One of the medical complications due to alcoholism is alcoholic liver disease. It is not only caused by alcohol itself but also risk increases due to deficiency of nutrients like carotenoids, vitamin A & K.

Pancreatitis due to alcoholism may be due to protein deficiency.

Nutrients, especially thiamine deficiency due to alcoholism can lead to severe and permanent damage of brain function and neurological problem such as impaired movement and memory loss.

Alcohol has toxic effects on fetal development, causing alcohol related birth defects, including fetal alcohol syndrome. Not only the insufficient nutrient intake by mother as compared to increased intake affects fetal development but also alcohol causes restriction of nutrition flow to fetus.